Continuous production of nanoforests

Patent metadata

Field	Value
Publication number	US-12060271-B2
Application number	US-202118015295-A
Country	US
Kind code	B2
Filing date	Jul 9, 2021
Priority date	Jul 9, 2020
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

Methods and apparatuses for continuous, large scale, commercially viable production of nanoforests. A roll-to-roll process passes a flexible substrate, including fibers and fabrics, through a furnace. Precursors are introduced in a growth zone in which a vertical or horizontal nanoforest of nanotubes or nanowires is grown on the substrate. Sensors and actuators with feedback control are provided for parameters such as substrate speed, substrate tension, furnace temperature, precursor flow rate, nanoforest thickness, and nanoforest. The furnace is preferably enclosed for environmental and safety purposes. The feed roll and take-up roll are disposed in housings can be attached to the furnace via airlocks, which enables rapid loading and unloading of the rolls using techniques well known in the industry while maintaining furnace conditions. The furnace can encompass flattening rollers and a second growth zone to enable manufacture of orthogonal nanoforests comprising a vertical nanoforest grown on a horizontal nanoforest.

First claim

What is claimed is:

1. A method for continuous production of nanoforests, the method comprising:
unrolling a flexible substrate from a feed roll into a first furnace;
growing a first nanoforest comprising first nanotubes or first nanowires on a surface of the substrate as it passes through a first growth zone in the first furnace, wherein the first nanotubes or first nanowires are oriented substantially perpendicular to the surface of the substrate;
cooling the first nanoforest in a first cooling zone;

rolling the first nanoforest through rollers to form a collapsed layer comprising the first nanotubes or first nanowires, wherein in the collapsed layer the first nanotubes or first nanowires are oriented substantially parallel to the surface of the substrate;
growing a second nanoforest comprising second nanotubes or second nanowires on the collapsed layer as it passes through a second growth zone, the second nanotubes or second nanowires oriented substantially perpendicular to the surface of the substrate;
cooling the second nanoforest in a second cooling zone; and
rolling the substrate comprising the first nanoforest and the second nanoforest onto a first take-up roll.

2. The method of claim 1 wherein the first nanotubes or first nanowires comprise carbon, BN, Si, CuO, or ZnO.

3. The method of claim 1 comprising maintaining tension on the flexible substrate.

4. The method of claim 1 performed simultaneously on multiple parallel substrates.

5. The method of claim 4 wherein the multiple parallel substrates are arranged vertically or horizontally relative to each other.

6. The method of claim 1 further comprising, between the step of cooling the first nanoforest and the step of rolling the first nanoforest through rollers:
rolling the substrate comprising the first nanoforest onto a second take-up roll; and
unrolling the substrate comprising the first nanoforest from the second take-up roll.

7. The method of claim 6 wherein the second growth zone is located in a second furnace.

8. The method of claim 6 further comprising:
inserting a first separator between adjacent layers of the substrate comprising the first nanoforest during the step of rolling the substrate comprising the first nanoforest onto a second take-up roll;
removing the first separator during the step of unrolling the substrate comprising the first nanoforest from the second take-up roll; and
inserting a second separator between adjacent layers of the substrate comprising the first nanoforest and the second nanoforest during the step of rolling the substrate comprising the first nanoforest and the second nanoforest onto a first take-up roll.

9. The method of claim 8 wherein the first separator and/or the second separator comprises a polyimide film.

10. The method of claim 8 further comprising, when the first furnace is enclosed during operation and the second take-up roll is full:
closing an airlock between an enclosure housing the second take-up roll and the first furnace;
unloading the second take-up roll;
loading a new empty take-up roll in place of the second take-up roll;
purging the enclosure; and
opening the airlock.

11. The method of claim 1 comprising controlling one or more parameters selected from the group consisting of unrolling speed, rolling speed, substrate tension, precursor flow rate, carrier gas flow rate, furnace temperature, and preheater temperature.

12. The method of claim 1 comprising measuring a thickness of the first nanoforest and/or the second nanoforest during the growing step.

13. The method of claim 1 wherein the first furnace is enclosed during operation.

14. The method of claim 13 further comprising, when the feed roll runs out of substrate:
closing an airlock between an enclosure housing the feed roll and the first furnace;
loading a new feed roll;
splicing the substrate on the feed roll and the substrate on the new feed roll;
purging the enclosure; and
opening the airlock.

15. The method of claim 13 further comprising, when the first take-up roll is full:
closing an airlock between an enclosure housing the first take-up roll and the first furnace;
unloading the first take-up roll;
loading a new empty take-up roll in place of the first take-up roll;
purging the enclosure; and
opening the airlock.

16. The method of claim 1 wherein the substrate comprises fibers, a fabric, or a flexible metal.

17. The method of claim 1 wherein the step of growing the first nanoforest and/or the step of growing the second nanoforest comprises growing the nanoforest on both sides of the substrate.

18. The method of claim 1 further comprising separating the second nanoforest and the collapsed layer from the substrate after the step of cooling the second nanoforest.

19. The method of claim 1 wherein the second growth zone is located in the first furnace.

Assignees

• Univ Hawaii
• Goodman Tech Llc

Inventors

• Ghasemi-Nejhad Mohammad Naghi
• Gudapati Vamshi M
• Taeb Pouria
• Minei Brenden M
• Goodman William A

Classifications

• F27B2009/2446

  with means to control the tension of the band · CPC title

• F27B9/243

  Endless-strand conveyor · CPC title

• C23C16/56

  After-treatment · CPC title

• C23C16/545

  for coating elongated substrates · CPC title

• C23C16/45565

  Shower nozzles · CPC title